package com.service.Authorization.util;


import cn.hutool.core.codec.Base64;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.springframework.stereotype.Component;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.*;
import java.security.spec.InvalidParameterSpecException;
import java.util.Arrays;


/**
 * @Author: wangqieyu
 * @Description: ${description}
 * @Date: 2020/10/20 16:31
 */
@Component
public class AESCBCUtil {



    /**
     * AES解密
     *
     * @param encryptedData  包括敏感数据在内的完整用户信息的加密数据，
     * @param key    秘钥
     * @param iv     加密算法的初始向量，
     * @param encodingFormat 解密后的结果需要进行的编码
     * @return String
     * @see  Exception
     */
    public static String decrypt(String encryptedData,String key, String iv,String encodingFormat) {
//        initialize();

        //被加密的数据
        byte[] dataByte = Base64.decode(encryptedData);
        //加密秘钥
        byte[] keyByte = Base64.decode(key);
        //偏移量
        byte[] ivByte = Base64.decode(iv);

        try {
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");

            SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");

            AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
            parameters.init(new IvParameterSpec(ivByte));
            // 初始化
            cipher.init(Cipher.DECRYPT_MODE, spec, parameters);
            byte[] resultByte = cipher.doFinal(dataByte);
            if (null != resultByte && resultByte.length > 0) {
                String result = new String(resultByte, encodingFormat);
                return result;
            }
            return null;
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidParameterSpecException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return null;
    }
    public static void main(String[] args) {
        String result = decryptData(
                "aek+OAPZDBb+wp3+A5oxhEK1oPOCaDJu/R0nncEsOzE8IlezlNbAVIfi7yRRWkQWJIsYQLiiEwegBBhzWTzBSYutHfh/UDE/6lpQloerztHe7kLA+rvUJJ/tgFOB3rxjl2TJ1FZHawQQLYxJCUHHxZjkj1HO/qqDgk3e3pgZxQ3kkl5RrYvhWAXaZUoWNdkPjW4PlMDqzBcDHbvmqPUv2Q==","SrMtUjIrc23tYpSs7/qDiw==",
                "cEB09agUki5v1Z1ozvn0qQ=="
        );
        System.out.println("result = " + result);
    }

    public static String decryptData(String encryptDataB64, String sessionKeyB64, String ivB64) {
        return new String(
                decryptOfDiyIV(
                        Base64.decode(encryptDataB64),
                        Base64.decode(sessionKeyB64),
                        Base64.decode(ivB64)
                )
        );
    }

    private static final String KEY_ALGORITHM = "AES";
    private static final String ALGORITHM_STR = "AES/CBC/PKCS7Padding";
    private static Key key;
    private static Cipher cipher;

    private static void init(byte[] keyBytes) {
        // 如果密钥不足16位，那么就补足.  这个if 中的内容很重要
        int base = 16;
        if (keyBytes.length % base != 0) {
            int groups = keyBytes.length / base + (keyBytes.length % base != 0 ? 1 : 0);
            byte[] temp = new byte[groups * base];
            Arrays.fill(temp, (byte) 0);
            System.arraycopy(keyBytes, 0, temp, 0, keyBytes.length);
            keyBytes = temp;
        }
        // 初始化
        Security.addProvider(new BouncyCastleProvider());
        // 转化成JAVA的密钥格式
        key = new SecretKeySpec(keyBytes, KEY_ALGORITHM);
        try {
            // 初始化cipher
            cipher = Cipher.getInstance(ALGORITHM_STR, "BC");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 解密方法
     *
     * @param encryptedData 要解密的字符串
     * @param keyBytes      解密密钥
     * @param ivs           自定义对称解密算法初始向量 iv
     * @return 解密后的字节数组
     */
    private static byte[] decryptOfDiyIV(byte[] encryptedData, byte[] keyBytes, byte[] ivs) {
        byte[] encryptedText = null;
        init(keyBytes);
        try {
            cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(ivs));
            encryptedText = cipher.doFinal(encryptedData);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return encryptedText;
    }

}
